Aqueous solubility of ciprofloxacin in the presence of metal cations

Purpose: Though the complexation of ciprofloxacin with metal cations has been extensively studied, the effect of this complexation on the aqueous solubility of ciprofloxacin which is an important factor affecting drug distribution has not been well documented. We have thus set out in this study to investigate the aqueous solubility of ciprofloxacin in the presence of metal cations. Method: The measurements were done spectrophometrically after shaking ciprofloxacin alone or in the presence of varying amounts of different metal cations for five hours to attain equilibrium. The amount of ciprofloxacin in the saturated solution in each case was then measured spectrophotometrically Results: The solubility of ciprofloxacin in 0.05M H2SO4 at 37.0 ± 0.20C was 46.65 mgml-1 (0.12M). Except for magnesium sulphate, all the cations investigated progressively increased the aqueous solubility of ciprofloxacin. Ferrous ion had the greatest increase. It was followed by ferric, calcium and aluminium ions. Potassium and sodium ions had very slight increase in ciprofloxacin solubility. As the amount of magnesium sulphate increased, the aqueous solubility of ciprofloxacin increased slightly initially but then decreased progressively. Conclusion: The observed solubility profiles can be attributed to the type and extent of complexes formed between ciprofloxacin and the metal cations. This increase in the aqueous solubility of ciprofloxacin can have profound effect on the enteric absorption of ciprofloxacin and on its antibacterial activity when these metal cations are present, and may contribute to the observed poor availability and antibacterial activity of ciprofloxacin when co-administered with these cations. Keywords: Ciprofloxacin, aqueous solubility, ciprofloxacin-metal cation, interaction, antibacterial activity, gastrointestinal absorption.> Tropical Journal of Pharmaceutical Research Vol. 4 (1) 2005: pp. 349-35

Analytical profile of the fluoroquinolone antibacterials. I. Ofloxacin

In recent years, there has been rapid progress in quinolone research and development resulting in the production of many clinically important fluoroquinolones which have been subjected to diverse analytical or assay methods. This is the first review article in this series of the fluoroquinoloneantibacterial agents with focus on the analytical profile of ofloxacin. Ofloxacin and indeed all the other fluoroquinolones are synthetic antibacterial agents structurally related to nalidixic acid. This articleexamines the synthesis, physico-chemical properties and analytical methods that have been used for the determination of ofloxacin in pharmaceutical dosages forms and biological fluids. The currentrelevant analytical trends and prospective analytical methods for ofloxacin have been presented and discussed

Assessment of nutritional status of soil supporting coconut (Cocus nucifera) cultivation in some localities of Edo State of Nigeria

Coconut cultivation and information on the nutritional status of soils and fertilizers recommendations for its cultivation are limited in Nigeria. Since a high yield of coconut is related to the fertility status ofthe soil, a study was conducted to evaluate the status of soils supporting coconut cultivation. The evaluation of the surface soil (0 – 15 cm) and the subsoil (15 – 30 cm) of seven localities showed thatthe average pH was 5.75 ± 0.21 and 5.51 ± 0.15, respectively, indicating that the subsoil was slightly acidic than the surface soil. Highest values for the surface soil parameters were found to be 0.58 ± 0.08 gkg-1 for exchangeable acidity, 2.55 ± 0.02 gkg-1 for organic carbon (C), 0.13 ± 0.02 gkg-1 for total nitrogen (N), 20.24 ± 1.10 gkg-1 for the carbon : nitrogen ratio, 17.45 ± 0.60 for available phosphorus (P), 0.21 ± 0.02 Cmolkg-1 for sodium (Na), 0.14 ± 0.01 Cmolkg-1 for potassium (K), 2.91 ± 0.10 Cmolkg-1 for calcium (Ca) and 0.79 ± 0.06 Cmolkg-1 for magnesium (Mg). On the other hand, the subsoil parameters were 0.74 ± 0.15 gkg-1 for exchangeable acidity, 1.85 ± 0.03 gkg-1 for organic C, 0.09 ± 0.01gkg-1 fortotal N, 19.69 ± 0.67 gkg-1 for the carbon : nitrogen ratio, 10.15 ± 0.38 for available P, 0.16 ± 0.01 Cmolkg- 1 for Na, 0.09 ± 0.01 Cmolkg-1 for K, 1.59 ± 0.04 Cmolkg-1 for Ca and 0.46 ± 0.04 Cmolkg-1 for Mg. The results showed the samples were not generally ideal for coconut growth and production of good yields because of marginal deviation from acceptable limits. It is recommended that the soils in these localities need fertilization especially with nitrogen and potassium carriers for the purpose of coconut cultivation

Effect of Exchange Rate Misalignment on Bilateral Trade Between Kenya and European Union: 2000-2016

The exchange rate is an important variable in international trade because a country's competitiveness is determined by the expectations on how trade reacts to its movements. To orient the economy outwards, Kenya has pursued various measures from the 1990s to the 2000s. Kenya also signed up for nonreciprocal trade with the European Union under the Cotonou agreement. Despite the export-oriented efforts, Kenya's trade has remained skewed towards imports and a widening trade deficit which seems to follow the weakening of the Kenya shilling. The main policy dilemma therefore, is how imports accelerated in an environment of unhindered European Union market access, hence the motivation of this study. The study adopted a dynamic modeling approach since previous and present values affect exchange rate and trade. The results show that the economic fundamentals drive the real exchange rate. In terms of misalignment, the exchange rate is overvalued to a maximum of 5.9 percent and undervalued up to 5.2 percent. The estimated misalignment hurts imports but has a positive, statistically insignificant effect on exports. The results of this study suggest that the monetary authority should ensure the exchange rate remains stable and within the 6 percent range while monitoring all the underlying determinants. Additionally, hedging instruments should be made available and affordable to traders

Comparative evaluation of selected starches as adsorbent for Thin-layer Chromatography

Purpose: A variety of tested organic and inorganic adsorbents are available today specifically for thin-layer chromatography. The most commonly used is silica gel which is an inorganic adsorbent. Organic substances like cellulose, polyethylene are also used. All these are imported into Nigeria and are unhealthy for economic policies. Most commonly used adsorbent may not be easy to produce locally, but starch, which is a very common product, can be made very readily available. Method: Comparative tests were carried out on cassava, guinea corn and irish potato starches to evaluate and determine suitability as adsorbents for thin-layer chromatography. The starches were used in their natural forms and various modified forms:- formamide, paraffin-impregnated forms and derivatized forms so as to exhibit different properties using different solvent systems to separate different classes of compounds namely alkaloids, amine acids, lipids and steroids with silica gel as standard. Results: The results obtained have proved starch to be a suitable adsorbent both in its naturally occurring and modified forms. Good separations of amino acids and steroids were obtained on natural layers when compared with silica gel, while alkaloids on formamide-impregnated layers and lipids on paraffin-impregnated layers also gave encouraging results. The acetylated starch by suitable modification should produce good results. Conclusion: The suitability of natural starches and its modifications as adsorbents for TLC has thus been established and seems very promising for future use. Keywords: Starch, cassava, guinea corn, Irish potato, adsorbent, thin-layer chromatography. > Tropical Journal of Pharmaceutical Research Vol. 4 (1) 2005: pp. 331-33

Phytochemical analysis and antioxidant evaluation of lemon grass (Cymbopogon citratus DC.) Stapf leaves

Cymbopogon citratus commonly called lemon grass is claimed to possess diverse medicinal value among different cultures. The present study determined the phytochemicals and evaluated the antioxidant potential of Cymbopogon citratus leaves. The phytochemical and proximate analysis of the powdered leaves were carried out using standard methods. The antioxidant activity of the crude methanol extract and its fractions (n-hexane, ethyl acetate and chloroform) was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays. The total phenolic and flavonoid contents were assessed using the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The phytochemical analysis revealed the presence of carbohydrates, reducing sugars, saponins, tannins, flavonoids and other phenolics compounds. The moisture, ash, fat, crude fibre, crude protein, water soluble ash and acid insoluble ash contents were 13.00%, 7.63%, 2.44%, 29.40%, 4.45%, 6.13% and 4.00%, respectively. Among the extract and fractions tested, the ethyl acetate fraction exhibited the highest antioxidant activity. The ethyl acetate fraction also had the highest phenolic and flavonoid contents. There was a strong relationship between the polyphenolic content and antioxidant activity of the extract and fractions with a coefficient of determination (r²) of 0.889 and 0.920 for total phenols and total flavonoids, respectively. The present study showed that the leaves of Cymbopogon citratus especially the ethyl acetate fraction possess good antioxidant activity and could serve as potentially source of natural antioxidants.Keywords: Medicinal plants, Lemon grass, Cymbopogon citratus, Phytochemicals, antioxidant

Identification of Counterfeit Drugs by Community Pharmacists in Lagos State

Purpose: The problem of fake and counterfeit drugs is real and constitutes a major threat to the health and safety of the Nigerian population. A descriptive study was carried out to assess the methods of identification of counterfeit drugs by community pharmacists in Lagos State. Methods: The research instrument was a 23-item questionnaire, which was administered to consenting community pharmacists in 17 out of the 20 Local Government Areas in Lagos State. A convenient sample of practicing community pharmacists both in retail and wholesale distribution of pharmaceutical products were recruited into the study using a list of registered pharmacists from the Association of Community Pharmacists in Lagos State. Effort was made to ensure adequate representation of Pharmacies in every local government area in Lagos State. Results: All the respondents agreed that there is a fake and counterfeit drug problem in Nigeria, and (74%) considered this a major problem. The respondents commonly used visual security techniques before drug purchasing. These were: Seals/embossments (83%), character of print (77%), and Holograms (68%).The respondents' most likely action after a counterfeit drug encounter was to return the drug back to the supplier. Conclusion: The study showed that pharmacists sampled were aware of the prevalence of fake and counterfeit drugs and quite a number of them have had encounters with them. There is an indication that the respondents try to assure themselves of the quality of the drugs they purchase by use of several methods. However, no rigorous effort was taken to confirm as well as report suspected fake and counterfeit drugs to regulatory authorities. Keywords: Community pharmacists, drug identification, fake and counterfeit drugs. > Tropical Journal of Pharmaceutical Research Vol. 5 (1) 2006: pp. 545-55

Effect of Ascorbic Acid on Pharmacokinetic Profile of Artemether in Male Rabbits (Oryctolagus cuniculus)

Malaria is one of the major public health challenges in Nigeria. Treatment failure as a result of drug interaction is a major problem. A study of the effect of ascorbic acid on the antiplasmodial activity of artemether has been reported. This study was carried out to determine the effect of ascorbic acid on the pharmacokinetic profile of artemether. Fourteen male rabbits weighing between 2.0 – 2.5 kg were used in this study. Four of the rabbits were used for determination of the efficiency, recovery studies and calibration curve while ten rabbits were randomly selected into Group A and B consisting of five rabbits each were used for the pharmacokinetic studies. Group A was administered a single dose of 10 mg/kg artemether while Group B was co-administered a single dose of 10 mg/kg artemeter and10 mg/kg ascorbic acid intramuscularly. The dihydroartemisinin in the plasma was analysed using High Performance Liquid Chromatography. The results showed that ascorbic acid affect the pharmacokinetic parameters of artemether. The time to reach maximum concentration (Tmax) increase from 30.00 min to 42.00 min while the maximum concentration (Cmax) and Area-under the Concentration Curve (AUC) decrease from 1461.9 (ng/mL) and 6566.7 (ng hr/mL) to 1331.1 (ng/mL) and 6105.8 (ng hr/mL), respectively. Ascorbic acid altered the pharmacokinetic profile of artemether. In clinical practice patients should be adviced not to co-administer ascorbic acid with artemether

The aqueous solubility of ofloxacin in the presence of metallic cations

Ofloxacin belongs to the class of fluoroquinolones which has found widespread use in the treatment of microbial infections resistant to  other antibiotics. However, metallic cations and anti-acids have been found to adversely affect the bioavailability and antibacterial activity of ofloxacin. Many reasons have been suggested to explain the observed effects. In order to gain further understanding of how ofloxacin-metallic cation interaction affects ofloxacin availability and activity, the aqueous solubility of ofloxacin was investigated in the presence of some metallic cations spectrophometrically in this study. All the cations investigated increased the aqueous solubility of ofloxacin to varying extents. Ferrous sulphate produced the greatest increase in the solubility of ofloxacin. It was followed by ferric ammonium citrate, magnesium sulphate, aluminium hydroxide and calcium carbonate. Potassium chloride and sodium bicarbonate produced very slight increases. In all the cases, the solubility of ofloxacin increased as the amount of each metallic cation increased. The observed results can be attributed to formation of soluble ionic ofloxacin carboxylate salts and complexes of the metallic cations. The implication of such increase of the aqueous solubility of ofloxacin in the presence of metallic cations on the bioavailability and antibacterial activity of ofloxacin is discussed

Spectrophotometric assay of artesunate using benzaldehydes with electron withdrawing substituents

Different analytical methods have been reported for the assay of artesunate. However, these methods require the use of sophisticated and expensive equipment and reagents which are not readily available in many developing countries like Nigeria. This study is aimed at developing a method that is accurate, simple and cost effective using readily available reagents for the assay of artesunate in pure form and in pharmaceutical formulations. The developed spectrophotometric assay method is based on the fact that reactive methylene centre of the acid decomposed product of artesunate readily donates a proton that reacts with benzaldehyde to form a chromogen. This study involves the use of two benzaldehydes with electron withdrawing substituents, 3-bromobenzaldehyde and 4-chlorobenzaldehyde. Both gave immediate yellow coloured products and the wavelength of maximum absorption for the product obtained using 3-bromobenzaldehyde was 452 nm, while it was 456 nm for the product obtained with 4-chlorobenzaldehyde. However, the dissolution of 3-bromobenzaldehyde was incomplete in the acidic medium. The result obtained with 4-chlorobenzaldehyde revealed that Beer’s law was obeyed at the range of 20-100 μg/ml artesunate concentration with a linear coefficient of 0.9996 and the molar absorptivity was 2.1261×103 mol-1 cm-1. The limits of detection and quantification were 1.3832 μg/ml and 4.6109 μg/ml, respectively. The method required water as diluent. The result obtained from recovery studies by standard addition method confirmed that there was no interference from pharmaceutical excipients. The developed method was used to assay five brands of artesunate tablets successfully. The results compared favourably well with those obtained using the method described in the International Pharmacopoeia.Keywords: Artesunate, Benzaldehydes, spectrophotometry, recovery studie